1. Technical Field
The present invention relates to shockproof sleeves for electronic products, and more particularly, to a gas column structure for a shockproof sleeve.
2. Description of Related Art
Shockproof sleeves are extensively used to wrap and protect electronic products, such as projectors, DVD, digital cameras, laptop computers and mobile phones. The electronic products in early times were rarely provided with display screens and even those with screens had relatively small screens. However, the trend for modern portable electronic products, such as mobile phones and game players, is that the screens equipped are increasingly enlarged. In the event that these modern portable electronic products get impacted at the screens, the screens are likely to be damaged and then the whole electronic products become unusable. Thus, shockproof sleeves have been developed with increasingly launched portable electronic products, such as those for mobile phones, digital cameras, and particularly, for laptop computers, so as to prevent electronic products from being damaged when they are being carried with people.
Traditionally, shockproof sleeves are designed as simple packaging. A conventional shockproof sleeve is typically a plastic sheet formed with a plurality of small raised air bubbles. In use, the shockproof sleeve wraps an article to be protected for absorbing shake and buffing. However, those small air bubbles have only limited shock-absorbing capability and may fail to provide shockproof and buffing effects against heavy shock or impact. Such a shockproof sleeve is typically made of EVA, which is an environmentally friendly plastic foaming material, and provides excellent shockproof and waterproof functions, while being antiseptic, non-toxic, non-pollutant and safe. However, in view that EVA is relatively costly, air-filled packaging bags have been developed as a new packaging and buffing material.
For example, there is a vertical hammock type air shockproof sleeve on the market for packing and protecting articles. Such an air shockproof sleeve is formed with a plurality of gas columns and a plurality of folding nodes. The gas columns are arranged along the folding nodes to form a base and buffer portions at two sides of the base with an accommodating space defined between the base and the buffer portions. The air shockproof sleeve further has at least one buffer sheet that has its two sides connected to the buffer portions and suspends in the accommodating space. However, when an article is received in the accommodating space, the article is not tightly close to the buffer portions and tends to shake and rock in the accommodating space, so the sleeve can get pierced by sharp corners or hardware joints of the article. Once the sleeve is broken, air filled therein will leak out and the article losing protection may be impacted or scraped.
Another example is a hammock type air shockproof sleeve, which has a first buffer wall and a second buffer wall formed with a first node and a second node, respectively. After the first buffer wall is bent against the first node and the second buffer wall is bent against the second node, the first buffer wall has its first edge bound with a second edge of the second buffer wall by neat sealing, so that an accommodating space is formed between the first buffer wall and the second buffer wall. A buffer sheet suspends in the accommodating space for wrapping an article to be protected and preventing the article from shaking, while the first buffer wall and the second buffer wall protect the article as well. Although there are two buffer walls, namely the first buffer wall and the second buffer wall, the accommodating space is not flat-bottomed, so when the article is placed at the edges near where the nodes are formed, the article having its weight pressing on the gas columns may pierce the gas columns to cause air leakage. As a result, the air shockproof sleeve will lose its protective function.
Taiwan Patent Application No. 200740667, titled as “Gas-filled packing bag with multiple auxiliary gas columns” has disclosed a packing bag composed of a plurality of gas column sets. Each said set includes a main gas column relatively larger in width and a first as well as a second auxiliary gas column relatively small in width. Particularly, the main gas column has a width 1-2 cm larger than that of the first and second auxiliary gas column. Between the main gas column and the first auxiliary gas column, and between the first auxiliary gas column and the second auxiliary gas column, there are heat sealing lines defining the gas columns as individuals. Along each of the heat sealing lines, one transverse channel is formed every 10-15 cm for air communication between the main gas column and the first or second auxiliary gas column while no such channel is provided along the heat sealing line between two adjacent gas column sets. Thus, the gas column sets are independent of each other without air communication therebetween. Thereby, breakage and gas leakage of the main gas column and/or the auxiliary gas columns of one gas column set will not affect the airtightness of other gas column sets. When the bag receives significant impact, gas will travel from the main gas column through the channel to the first auxiliary gas column, and then travel form the first auxiliary gas column through the channel to the second auxiliary gas column, vice versa, until the pressure balance is established among the auxiliary gas columns and the main gas column. In virtue of the plural auxiliary gas columns, the capacity of the main gas column is enhanced, and the shockproof ability of the packing bag is improved. While the prior-art gas-filled packing bag with multiple auxiliary gas columns is capable of bearing heavy impact, it is not suitable for packing articles with sharp points and it fails to propose a solution for the folds at the corners of the bag caused by bent gas columns.